To meet the demand for wireless data traffic, which has increased since deployment of 4th-generation (4G) communication systems, efforts have been made to develop an improved 5th-generation (5G) or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a ‘beyond 4G network’ or a ‘post long-term evolution (LTE) system’.
It is considered that the 5G communication system will be implemented in millimeter wave (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To reduce propagation loss of radio waves and increase a transmission distance, a beam forming technique, a massive multiple-input multiple-output (MIMO) technique, a full dimensional MIMO (FD-MIMO) technique, an array antenna technique, an analog beam forming technique, and a large scale antenna technique are discussed in 5G communication systems.
In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, a device-to-device (D2D) communication, a wireless backhaul, a moving network, a cooperative communication, coordinated multi-points (CoMP), reception-end interference cancellation, and the like.
In the 5G system, a hybrid frequency shift keying (FSK) and quadrature amplitude modulation (QAM) modulation (FQAM) and a sliding window superposition coding (SWSC) as an advanced coding modulation (ACM) scheme, and a filter bank multi carrier (FBMC) scheme, a non-orthogonal multiple Access (NOMA) scheme, and a sparse code multiple access (SCMA) scheme as an advanced access technology have been developed.
Generally, a wireless communication system may be classified into a frequency division duplexing (FDD) scheme, a time division duplexing (TDD) scheme, and/or the like based on a type of a wireless resource, e.g., a frequency, a time, and/or the like. For example, an LTE scheme may be classified into an FDD LTE scheme and a TDD LTE scheme.
A communication scheme in a wireless communication system may be classified into a half-duplex scheme and a full-duplex scheme.
In the full-duplex scheme, downlink (DL) transmission and uplink (UL) transmission may be performed at the same time using the same wireless resource, e.g., at least one of the same frequency band and the same time interval.
In the half-duplex scheme, only one of DL transmission and UL transmission may be performed using the same wireless resource.
A wireless communication system supporting the half-duplex scheme will be referred to as half-duplex system, and a wireless communication system supporting the full-duplex scheme will be referred to as full-duplex system.
Generally, in a wireless communication system, the higher a transmission frequency is, the more decreased propagation path loss is. Due to this, a propagation range becomes relatively short, so a service area is decreased. A beamforming technology has been proposed as an important technology for mitigating propagation path loss and increasing a propagation range.
For example, a beamforming technology may be classified into a transmission beamforming technology and a reception beamforming technology. The transmission beamforming technology is a technology for concentrating a signal transmitted from each of a plurality of antennas in a transmitting side on a specific direction, and the reception beamforming technology is a technology for concentrating a plurality of antennas in a receiving side on a signal received from a specific direction. In this case, a form including the plurality of antennas will be referred to as antenna array. Antennas included in the antenna array will be referred to as array element antennas.
If the transmission beamforming technology is used, a propagation range of a transmission signal may be increased. Further, the transmission signal is little transmitted toward a direction different from a desired direction for the transmission signal, so interference to other user equipment (UE) may be decreased.
If the reception beamforming technology is used, reception for a propagation may be concentrated ton a specific direction, so sensitivity of a signal received in the specific direction may be increased. Further, a signal received in a direction, not the specific direction is excluded from a received signal, so interference due to the signal received in the direction, not the specific direction may be prevented.
Generally, if a plurality of UEs use the same wireless resource, e.g., the same frequency, the same time, and/or the like in a full-duplex system, interference among the plurality of UEs or interference in each UE may occur. For example, in a case that the same wireless resource is allocated on each of a UL which is permitted for to a Tx UE to use and a DL which is permitted for an Rx UE to use, if the Tx UE is relatively close to the Rx UE, severe inter-user-interference (IUI) may occur. Further, if a BS performs transmission and reception using the same wireless resource, self-interference (SI) may occur.
The IUI denotes interference which occurs according that a signal transmitted from a neighbor UE affects other UE. The SI denotes interference which occurs according that a transmission signal of a UE affects a reception signal of the UE in the UE.
So, there is a need for performing a beamforming operation for decreasing interference in a case that a full-duplex system transmits or receives a signal based on a beamforming technology.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.